Phoenix.Router
Phoenix.Router
Defines a Phoenix router.
The router provides a set of macros for generating routes that dispatch to specific controllers and actions. Those macros are named after HTTP verbs. For example:
defmodule MyApp.Router do
use Phoenix.Router
get "/pages/:page", PageController, :show
end
The get/3
macro above accepts a request of format "/pages/VALUE"
and dispatches it to the show action in the PageController
.
Routes can also match glob-like patterns, routing any path with a common base to the same controller. For example:
get "/dynamic*anything", DynamicController, :show
Phoenix’s router is extremely efficient, as it relies on Elixir pattern matching for matching routes and serving requests.
Helpers
Phoenix automatically generates a module Helpers
inside your router which contains named helpers to help developers generate and keep their routes up to date.
Helpers are automatically generated based on the controller name. For example, the route:
get "/pages/:page", PageController, :show
will generate the following named helper:
MyApp.Router.Helpers.page_path(conn_or_endpoint, :show, "hello")
"/pages/hello"
MyApp.Router.Helpers.page_path(conn_or_endpoint, :show, "hello", some: "query")
"/pages/hello?some=query"
MyApp.Router.Helpers.page_url(conn_or_endpoint, :show, "hello")
"http://example.com/pages/hello"
MyApp.Router.Helpers.page_url(conn_or_endpoint, :show, "hello", some: "query")
"http://example.com/pages/hello?some=query"
If the route contains glob-like patterns, parameters for those have to be given as list:
MyApp.Router.Helpers.dynamic_path(conn_or_endpoint, :show, ["dynamic", "something"])
"/dynamic/something"
The url generated in the named url helpers is based on the configuration for :url
, :http
and :https
.
The named helper can also be customized with the :as
option. Given the route:
get "/pages/:page", PageController, :show, as: :special_page
the named helper will be:
MyApp.Router.Helpers.special_page_path(conn, :show, "hello")
"/pages/hello"
Scopes and Resources
The router also supports scoping of routes:
scope "/api/v1", as: :api_v1 do
get "/pages/:id", PageController, :show
end
For example, the route above will match on the path "/api/v1/pages/:id"
and the named route will be api_v1_page_path
, as expected from the values given to scope/2
option.
Phoenix also provides a resources/4
macro that allows developers to generate “RESTful” routes to a given resource:
defmodule MyApp.Router do
use Phoenix.Router
resources "/pages", PageController, only: [:show]
resources "/users", UserController, except: [:delete]
end
Finally, Phoenix ships with a mix phoenix.routes
task that nicely formats all routes in a given router. We can use it to verify all routes included in the router above:
$ mix phoenix.routes
page_path GET /pages/:id PageController.show/2
user_path GET /users UserController.index/2
user_path GET /users/:id/edit UserController.edit/2
user_path GET /users/new UserController.new/2
user_path GET /users/:id UserController.show/2
user_path POST /users UserController.create/2
user_path PATCH /users/:id UserController.update/2
PUT /users/:id UserController.update/2
One can also pass a router explicitly as an argument to the task:
$ mix phoenix.routes MyApp.Router
Check scope/2
and resources/4
for more information.
Pipelines and plugs
Once a request arrives at the Phoenix router, it performs a series of transformations through pipelines until the request is dispatched to a desired end-point.
Such transformations are defined via plugs, as defined in the Plug specification. Once a pipeline is defined, it can be piped through per scope.
For example:
defmodule MyApp.Router do
use Phoenix.Router
pipeline :browser do
plug :fetch_session
plug :accepts, ["html"]
end
scope "/" do
pipe_through :browser
# browser related routes and resources
end
end
Phoenix.Router
imports functions from both Plug.Conn
and Phoenix.Controller
to help define plugs. In the example above, fetch_session/2
comes from Plug.Conn
while accepts/2
comes from Phoenix.Controller
.
Note that router pipelines are only invoked after a route is found. No plug is invoked in case no matches were found.
Summary
Macros
- connect(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a connect request to the given path
- delete(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a delete request to the given path
- forward(path, plug, plug_opts \\ [], router_opts \\ [])
-
Forwards a request at the given path to a plug
- get(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a get request to the given path
- head(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a head request to the given path
- match(verb, path, plug, plug_opts, options \\ [])
-
Generates a route match based on an arbitrary HTTP method
- options(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a options request to the given path
- patch(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a patch request to the given path
- pipe_through(pipes)
-
Defines a pipeline to send the connection through
- pipeline(plug, list)
-
Defines a plug pipeline
- plug(plug, opts \\ [])
-
Defines a plug inside a pipeline
- post(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a post request to the given path
- put(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a put request to the given path
- resources(path, controller)
-
See
resources/4
- resources(path, controller, opts)
-
See
resources/4
- resources(path, controller, opts, list)
-
Defines “RESTful” routes for a resource
- scope(options, list)
-
Defines a scope in which routes can be nested
- scope(path, options, list)
-
Define a scope with the given path
- scope(path, alias, options, list)
-
Defines a scope with the given path and alias
- trace(path, plug, plug_opts, options \\ [])
-
Generates a route to handle a trace request to the given path
Macros
connect(path, plug, plug_opts, options \\ [])
Generates a route to handle a connect request to the given path.
delete(path, plug, plug_opts, options \\ [])
Generates a route to handle a delete request to the given path.
forward(path, plug, plug_opts \\ [], router_opts \\ [])
Forwards a request at the given path to a plug.
All paths that matches the forwarded prefix will be sent to the forwarded plug. This is useful to share router between applications or even break a big router into smaller ones. The router pipelines will be invoked prior to forwarding the connection.
The forwarded plug will be initialized at compile time.
Note, however, that we don’t advise forwarding to another endpoint. The reason is that plugs defined by your app and the forwarded endpoint would be invoked twice, which may lead to errors.
Examples
scope "/", MyApp do
pipe_through [:browser, :admin]
forward "/admin", SomeLib.AdminDashboard
forward "/api", ApiRouter
end
get(path, plug, plug_opts, options \\ [])
Generates a route to handle a get request to the given path.
head(path, plug, plug_opts, options \\ [])
Generates a route to handle a head request to the given path.
match(verb, path, plug, plug_opts, options \\ [])
Generates a route match based on an arbitrary HTTP method
Useful for defining routes not included in the builtin macros:
get
, post
, put
, patch
, delete
, options
, connect
, trace
, head
Examples
match(:move, "/events/:id", EventController, :move)
options(path, plug, plug_opts, options \\ [])
Generates a route to handle a options request to the given path.
patch(path, plug, plug_opts, options \\ [])
Generates a route to handle a patch request to the given path.
pipe_through(pipes)
Defines a pipeline to send the connection through.
See pipeline/2
for more information.
pipeline(plug, list)
Defines a plug pipeline.
Pipelines are defined at the router root and can be used from any scope.
Examples
pipeline :api do
plug :token_authentication
plug :dispatch
end
A scope may then use this pipeline as:
scope "/" do
pipe_through :api
end
Every time pipe_through/1
is called, the new pipelines are appended to the ones previously given.
plug(plug, opts \\ [])
Defines a plug inside a pipeline.
See pipeline/2
for more information.
post(path, plug, plug_opts, options \\ [])
Generates a route to handle a post request to the given path.
put(path, plug, plug_opts, options \\ [])
Generates a route to handle a put request to the given path.
resources(path, controller)
See resources/4
.
resources(path, controller, opts)
See resources/4
.
resources(path, controller, opts, list)
Defines “RESTful” routes for a resource.
The given definition:
resources "/users", UserController
will include routes to the following actions:
-
GET /users
=>:index
-
GET /users/new
=>:new
-
POST /users
=>:create
-
GET /users/:id
=>:show
-
GET /users/:id/edit
=>:edit
-
PATCH /users/:id
=>:update
-
PUT /users/:id
=>:update
-
DELETE /users/:id
=>:delete
Options
This macro accepts a set of options:
-
:only
- a list of actions to generate routes for, for example:[:show, :edit]
-
:except
- a list of actions to exclude generated routes from, for example:[:delete]
-
:param
- the name of the parameter for this resource, defaults to"id"
-
:name
- the prefix for this resource. This is used for the named helper and as the prefix for the parameter in nested resources. The default value is automatically derived from the controller name, i.e.UserController
will have name"user"
-
:as
- configures the named helper exclusively -
:singleton
- defines routes for a singleton resource that is looked up by the client without referencing an ID. Read below for more information
Singleton resources
When a resource needs to be looked up without referencing an ID, because it contains only a single entry in the given context, the :singleton
option can be used to generate a set of routes that are specific to such single resource:
-
GET /user
=>:show
-
GET /user/new
=>:new
-
POST /user
=>:create
-
GET /user/edit
=>:edit
-
PATCH /user
=>:update
-
PUT /user
=>:update
-
DELETE /user
=>:delete
Usage example:
resources "/account", AccountController, only: [:show], singleton: true
scope(options, list)
Defines a scope in which routes can be nested.
Examples
scope "/api/v1", as: :api_v1, alias: API.V1 do
get "/pages/:id", PageController, :show
end
The generated route above will match on the path "/api/v1/pages/:id"
and will dispatch to :show
action in API.V1.PageController
. A named helper api_v1_page_path
will also be generated.
Options
The supported options are:
-
:path
- a string containing the path scope -
:as
- a string or atom containing the named helper scope -
:alias
- an alias (atom) containing the controller scope -
:host
- a string containing the host scope, or prefix host scope, ie"foo.bar.com"
,"foo."
-
:private
- a map of private data to merge into the connection when a route matches -
:assigns
- a map of data to merge into the connection when a route matches
scope(path, options, list)
Define a scope with the given path.
This function is a shortcut for:
scope path: path do
...
end
scope(path, alias, options, list)
Defines a scope with the given path and alias.
This function is a shortcut for:
scope path: path, alias: alias do
...
end
trace(path, plug, plug_opts, options \\ [])
Generates a route to handle a trace request to the given path.
© 2014 Chris McCord
Licensed under the MIT License.
https://hexdocs.pm/phoenix/Phoenix.Router.html